package org.apache.maven.project.harness;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.jxpath.ri.Compiler;
import org.apache.commons.jxpath.ri.compiler.NodeNameTest;
import org.apache.commons.jxpath.ri.compiler.NodeTest;
import org.apache.commons.jxpath.ri.compiler.NodeTypeTest;
import org.apache.commons.jxpath.ri.model.NodeIterator;
import org.apache.commons.jxpath.ri.model.NodePointer;
import org.codehaus.plexus.util.StringUtils;
import org.codehaus.plexus.util.xml.Xpp3Dom;

/**
 * A node iterator for JXPath to support <code>Xpp3Dom</code>.
 * 
 * @author Benjamin Bentmann
 */
class Xpp3DomNodeIterator implements NodeIterator {

  private NodePointer parent;

  private NodeTest test;

  private Xpp3Dom node;

  private Xpp3Dom[] children;

  private List<Xpp3Dom> filteredChildren = new ArrayList<Xpp3Dom>();

  private int filteredIndex;

  private Xpp3Dom child;

  private int position;

  public Xpp3DomNodeIterator(NodePointer parent, NodeTest test, boolean reverse, NodePointer startWith) {
    this.parent = parent;
    this.node = (Xpp3Dom) parent.getNode();
    this.children = this.node.getChildren();
    if (startWith != null) {
      for (; filteredIndex < children.length; filteredIndex++) {
        if (startWith.equals(children[filteredIndex])) {
          filteredIndex++;
          break;
        }
      }
    }
    this.test = test;
    if (reverse) {
      throw new UnsupportedOperationException();
    }
  }

  public NodePointer getNodePointer() {
    if (position == 0) {
      setPosition(1);
    }
    return (child == null) ? null : new Xpp3DomNodePointer(parent, child);
  }

  public int getPosition() {
    return position;
  }

  public boolean setPosition(int position) {
    this.position = position;
    filterChildren(position);
    child = (position > 0 && position <= filteredChildren.size()) ? filteredChildren.get(position - 1) : null;
    return child != null;
  }

  private void filterChildren(int position) {
    for (; position > filteredChildren.size() && filteredIndex < children.length; filteredIndex++) {
      Xpp3Dom child = children[filteredIndex];
      if (testNode(child)) {
        filteredChildren.add(child);
      }
    }
  }

  private boolean testNode(Xpp3Dom node) {
    if (test == null) {
      return true;
    }
    if (test instanceof NodeNameTest) {
      String nodeName = node.getName();
      if (StringUtils.isEmpty(nodeName)) {
        return false;
      }

      NodeNameTest nodeNameTest = (NodeNameTest) test;
      String namespaceURI = nodeNameTest.getNamespaceURI();
      boolean wildcard = nodeNameTest.isWildcard();
      String testName = nodeNameTest.getNodeName().getName();
      String testPrefix = nodeNameTest.getNodeName().getPrefix();
      if (wildcard && testPrefix == null) {
        return true;
      }
      if (wildcard || testName.equals(nodeName)) {
        return StringUtils.isEmpty(namespaceURI) || StringUtils.isEmpty(testPrefix);
      }
      return false;
    }
    if (test instanceof NodeTypeTest) {
      switch (((NodeTypeTest) test).getNodeType()) {
        case Compiler.NODE_TYPE_NODE:
          return true;
        case Compiler.NODE_TYPE_TEXT:
          return node.getValue() != null;
        default:
          return false;
      }
    }
    return false;
  }

}
